This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. For social animals to react appropriately to each other they need to know about each others'gender, social status, and the state they are in (such as whether they are hungry, distressed, fearful, or aggressive). The purpose of this study is to illuminate basic social cognition that is often taken for granted. The laboratory at the Yerkes Primate Center serves the education of a great many undergraduate and graduate students, who obtain valuable training in combination with classes they take. Available to them are 30 brown capuchin monkeys (Cebus apella), kept in indoor/outdoor enclosures that are trained for temporary separation for experiments. Research on this study concerns prosocial tendencies. It is often assumed that only humans show such tendencies, i.e. act prosocially if there is nothing to be gained from doing so. But in this study, capuchin monkeys chose to reward a partner together with themselves over just rewarding themselves for a task. Our work continues with face recognition in monkeys, which matches or exceeds the face recognition found in macaques, and may be closer to that found in chimpanzees.